Long- and short-term exposure to particulate matter smaller than 2.5 μm diameter (PM 2.5) is linked to a wide range of harmful cardiovascular and respiratory health effects [1]. The US Environmental Protection Agency revised the annual average PM 2.5 concentration limit in 2013 from 15 to 12 μg/m3 and estimated that meeting the new standard will result in $4 to $9 billion in annual health benefits [2]. The concentration level of PM 2.5 is currently monitored by sparsely distributed monitoring stations set up by environment agencies to assess air quality in different regions.
There is a need for cost effective ways to monitor local personal exposure to particulate matter in air especially in densely populated cities and hazardous occupational environments (where the concentration level frequently exceeds the recommended limits). There is a particular need for such ways which are capable of real-time monitoring (e.g. capable of completing a measure of a level of particulates in a few minutes—such as less than 15 minutes or less than 7 minutes). Advantageously such ways would be capable of determining particle concentrations according to accepted standards such as PM2.5.